(19)
(11) EP 0 285 128 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
25.10.1989 Bulletin 1989/43

(43) Date of publication A2:
05.10.1988 Bulletin 1988/40

(21) Application number: 88105175.9

(22) Date of filing: 30.03.1988
(51) International Patent Classification (IPC)4: C21D 3/00, C21D 6/00, C22C 38/38
(84) Designated Contracting States:
DE FR GB

(30) Priority: 30.03.1987 JP 76630/87

(71) Applicant: KABUSHIKI KAISHA TOSHIBA
Kawasaki-shi, Kanagawa-ken 210 (JP)

(72) Inventors:
  • Tada, Kaoru
    Isehara-shi Kanagawa-ken (JP)
  • Hasunuma, Masahiko
    Yokohama-shi Kanagawa-ken (JP)
  • Kawai, Mitsuo
    Yokohama-shi Kanagawa-ken (JP)

(74) Representative: Hansen, Bernd, Dr.rer.nat. et al
Hoffmann, Eitle & Partner Patentanwälte Postfach 81 04 20
81904 München
81904 München (DE)


(56) References cited: : 
   
       


    (54) Manufacturing method for high hardness member


    (57) A metal molded shape having a high hardness surface layer which is hard to work is obtained by casting an easy to work alloy member into a desired molded form, and then changing the composition of the member surface by volatilizing off the high vapor pressure elements, carried out by subjecting the easy to work alloy member, to a heat treatment at high temperature.





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